I love my owners locker! I have extra plastic hangars, coffee, coffee filters, poncho's, a first aid kit, extra toothbrushes, hair care, liquid soap, etc.
With the airlines now charging for checked bags, I think it's a great idea. Especially if you're lucky enough to get to WDW every year or more than once a year. The WDW resorts are well aware of what an owners locker is, so it's waiting at bell services for you. However, the owner's locker company (John & Brian) will also deliver to other local hotels, and resorts. (ask them to make sure yours is in delivery range).
I've always gotten great service from this company. I'm really happy with them. In my opinion, it's well worth it.